1. Field of the Invention
This invention relates to a continuous flow instrument which may be used as a hysteroscope or cystoscope and more particularly relates to a continuous flow hysteroscope having an outer sheath which has a hollowed-out central area which terminates in a distal end and a means for defining an inner member which is located within the hollowed-out central area wherein the means defining the inner member includes means for defining a first channel for receiving a telescope, and a second channel adjacent the first channel for passing a working tool. The outer wall of the first and second channels is spaced from the inner surface of the outer sheath to define a fluid passageway. An obturator closure means is used to isolate fluid flow and to aid in the insertion of the hysteroscope into the uterine cavity to reduce patient trauma. In a procedure, irrigation fluid is passed to the operative site by either one or both of the first channel and second channel to and out of the distal end. Fluid is removed from the operative site by passing the irrigation fluid through a plurality of openings in the distal section of the outer sheath into the fluid passageway to an outlet at the proximal end.
2. Description of the Prior Art
Continuous flow resectoscopes are well known in the art. U.S. Pat. No. 3,835,842 discloses a continuous flow resectoscope for use in urology. Continuous flow resectoscopes have been used for other surgical procedures. An article entitled, The Use of the Resectoscope in Gynecology, by Richard A. Auhll, appeared at pages 91 through 99 in the Oct. 11, 1990 issue of the Biomedical Business International (the "Auhll Reference") describes the use of the CIRCON ACMI uterine resectoscope system for gynecological procedures. The Auhll Reference discloses that the use of a continuous flow electrical resectoscope system (CFR) includes a continuous flow irrigation system. Multiple concentric sheaths allow continuous and simultaneous inflow and outflow of non-conducting irrigating solutions so that the surgeon has a clear view through the solution. It is known in the art that the means for passing fluid into the uterus in order to distend the same cannot exceed an intravesical pressure of 90 mm of mercury. If the fluid pressure exceeds 90 mm of mercury, then the fluid is absorbed into the tissue of the uterus which is undesirable in performing an OB-GYN procedure.
In addition, the continuous flow irrigation system provides sufficient flow and pressure to distend and expand the uterus to use the task of the surgeon. Such a system is referred to as a Uterine Resectoscope System. The Uterine Resectoscope System is used for three operative procedures: (i) Myoma resection; (ii) endometrial ablation; and (iii) synechial septo dissection.
The present known continuous flow resectoscope and hysteroscope systems generally pass an irrigating fluid through the center of an inner sheath and out of the distal end to irrigate the operative site. Fluid is removed from the operative site by passing the fluid through a passageway formed between the outer surface of an inner sheath and the inner surface of an outer sheath. Typically, fluid flow is obtained by positioning the source of fluid at a predetermined height in the operating room. For example, positioning a bag of fluid at approximately 1 meter above the operating table will produce 75 mm of mercury head pressure. At a height of 1.4 meter produces approximately 103 mm of mercury pressure at the outlet of the source. The pressure drop through the various tubing and through the resectoscope drops the pressure to a range of 60 mm of mercury to 90 mm of mercury at the distal end of the hysteroscope.